#include <REGX52.H>
#include "Delay.h"

/**
  * @brief  获取独立按键的键码
  * @param  无
  * @retval 范围0~4，无按键按下时返回0
  */
unsigned char Key() {
	unsigned char KeyNumber = 0;
	
	if (P3_1 == 0) {Delay(20); while (P3_1 == 0); Delay(20); KeyNumber = 1;}
	if (P3_0 == 0) {Delay(20); while (P3_0 == 0); Delay(20); KeyNumber = 2;}
	if (P3_2 == 0) {Delay(20); while (P3_2 == 0); Delay(20); KeyNumber = 3;}
	if (P3_3 == 0) {Delay(20); while (P3_3 == 0); Delay(20); KeyNumber = 4;}
	
	return KeyNumber;
}